The Inchoroi homeworld is not meaningless lol. The whole universe is meaningful in this story, that's the fundamental premise. Gods and souls are as real in an anarcane place as they are in an arcane place. Anarcane and arcane refer to sorcery, i.e. "co-opting" the song of the God of Gods. God dreams lucidly in anarcane places, so sorcery becomes impossible.
Where do you get this from. If the Gods don nor interact with their world, no sorcery, then it is meaningless. Know idea where you got this idea.
The explanation is in the post you quoted. The universe is meaningful, Gods, souls and Damnation are objectively and demonstrably real in this universe, that is why the Inchoroi set out on their quest for shutting off the Outside. This is the premise of the story.
You've read it wrong. And we have tons of evidence to the contrary. The 2 Inchoroi and a few human sorcerers found the NG. Figured out how it worked. Oh, added some chorale to it for defense against magic (which correct me if I'm wrong, Wilshire said the NG was magical), then Aurang knew it needed a inerrant. So, they start tossing in people, until one works, Nayu. Not the original. The Ark was an entity unto its own self. The Inchoroi called it mother. It didn't need a human to run on. Or, to sustain itself. No magic. All tekne.
My interpretation is, they found some knowledge (written or stored in some kind of Tekne device), which included the plans to the No-God, then created or found (can go both ways) the Sarcophagus without possessing the full understanding of its workings. For some reason they decided that a soul must power it. Might have been in the plans, might have been part of their ad-hoc solution. Long story short, they were right and after many tries it worked.
Bakker states that explicitly that the reason that Nau Cayuti could be used was because his brain structure emulated that of the
original insertant, which means that the No-God had insertants in previous incarnations. The supply of insertants and probably also a great deal of knowledge about how to activate the No-God was lost during Arkfall.